An imaging device capable of capturing still or moving pictures generally performs focusing and zooming operations by means of a focus actuator that drives one focus lens group, and a zoom actuator that drives one zoom lens group. A DC motor, a stepping motor, an ultrasonic motor, or the like is used for the focus actuator and the zoom actuator. The relative positions of the focus actuator and the zoom actuator can be ascertained with an encoder or the like, but the absolute positions are unknown, so a home point detecting sensor is used.
Japanese Laid-Open Patent Application 2010-79250 refers to an imaging device and a lens barrel capable of capturing still or moving pictures, wherein a zoom lens group is driven manually, and a focus lens group is driven by one actuator. The home point detecting sensor for the actuator is disposed in the center within the tracking range of the focus lens group.